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Richard Sherman had three tackles and a pass defensed in the Seahawks' Week 12 loss to Miami. (Steven Bisig-US PRESSWIRE)

A new, stunning twist to the NFC's wild-card chase: Seattle starting cornerbacks Brandon Browner and Richard Sherman both are facing four-game suspensions for violating the league's policy on performance-enhancing drugs.

ESPN's Adam Schefter first reported the news, which was confirmed by the NFL Network's Albert Breer. Schefter added that both Browner and Sherman plan to appeal, "insisting they are innocent." They will be able to play until the appeal process is finished.

According to USA Today's Mike Garafolo, Browner and Sherman tested positive for Adderall. If true, that would make the Seahawks' cornerbacks the latest players punished by the NFL's crackdown on the drug, which is used to treat ADHD, among other things. Atlanta center Joe Hawley, Tampa Bay cornerback Aqib Talib, and the Giants' Will Hill and Tyler Sash have all been suspended for Adderall use.

Unless Browner and Sherman manage to successfully reverse their punishments on appeal -- Giants' RB Andre Brown did so in the offseason -- then the Seahawks' chances at making the postseason will dwindle significantly. The Seahawks did welcome back Marcus Trufant from injury recently, but Browner and Sherman have started all 11 games at cornerback so far, combining for seven interceptions.

Seattle's next four games: at Chicago, Arizona, at Buffalo, San Francisco. It's a make-or-break stretch that includes matchups with elite receivers like Brandon Marshall and Larry Fitzgerald. Browner and Sherman would be eligible to return for a Week 17 game against St. Louis, plus the postseason.

Even getting to Week 17 with a shot at the playoffs, though, would be a tall task for Seattle minus its top two corners.